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package oracle.toplink.essentials.internal.ejb.cmp3.base;
import java.util.Enumeration;
import oracle.toplink.essentials.descriptors.ClassDescriptor;
import oracle.toplink.essentials.internal.descriptors.DescriptorIterator;
import oracle.toplink.essentials.internal.helper.IdentityHashtable;
import oracle.toplink.essentials.internal.localization.ExceptionLocalization;
import oracle.toplink.essentials.internal.sessions.UnitOfWorkImpl;
import oracle.toplink.essentials.exceptions.DatabaseException;
import oracle.toplink.essentials.exceptions.OptimisticLockException;
import oracle.toplink.essentials.internal.sessions.UnitOfWorkChangeSet;
import oracle.toplink.essentials.internal.sessions.ObjectChangeSet;
import oracle.toplink.essentials.mappings.ForeignReferenceMapping;
public class RepeatableWriteUnitOfWork extends UnitOfWorkImpl {
/** Used to store the final UnitOfWorkChangeSet for merge into the shared cache */
protected UnitOfWorkChangeSet cumulativeUOWChangeSet;
/** Used to store objects already deleted from the db and unregistered */
protected IdentityHashtable unregisteredDeletedObjectsCloneToBackupAndOriginal;
/** Used to determine if UnitOfWork should commit and rollback transactions
* This is used when an EntityTransaction is controlling the transaction
*/
protected boolean shouldTerminateTransaction;
/** Used to determine if UnitOfWork.synchronizeAndResume method should
* resume (the normal behaviour); or alternatively clear the UnitOfWork.
*/
protected boolean shouldClearForCloseInsteadOfResume = false;
public RepeatableWriteUnitOfWork(oracle.toplink.essentials.internal.sessions.AbstractSession parentSession){
super(parentSession);
this.shouldTerminateTransaction = true;
this.shouldNewObjectsBeCached = true;
}
/**
* INTERNAL:
* Call this method if the uow will no longer used for comitting transactions:
* all the changes sets will be dereferenced, and (optionally) the cache cleared.
* If the uow is not released, but rather kept around for ValueHolders, then identity maps shouldn't be cleared:
* the parameter value should be 'false'. The lifecycle set to Birth so that uow ValueHolder still could be used.
* Alternatively, if called from release method then everything should go and therefore parameter value should be 'true'.
* In this case lifecycle won't change - uow.release (optionally) calls this method when it (uow) is already dead.
* The reason for calling this method from release is to free maximum memory right away:
* the uow might still be referenced by objects using UOWValueHolders (though they shouldn't be around
* they still might).
*/
public void clearForClose(boolean shouldClearCache){
super.clearForClose(shouldClearCache);
this.cumulativeUOWChangeSet = null;
this.unregisteredDeletedObjectsCloneToBackupAndOriginal = null;
}
/**
* INTERNAL:
* Indicates whether clearForClose methor should be called by release method.
*/
public boolean shouldClearForCloseOnRelease() {
return true;
}
/**
* INTERNAL:
* Commit the changes to any objects to the parent.
*/
public void commitRootUnitOfWork() throws DatabaseException, OptimisticLockException {
commitToDatabaseWithChangeSet(false);
// unit of work has been committed so it's ok to set the cumulative into the UOW for merge
if(this.cumulativeUOWChangeSet != null) {
this.cumulativeUOWChangeSet.mergeUnitOfWorkChangeSet((UnitOfWorkChangeSet)this.getUnitOfWorkChangeSet(), this, true);
setUnitOfWorkChangeSet(this.cumulativeUOWChangeSet);
}
commitTransactionAfterWriteChanges(); // this method will commit the transaction
// and set the transaction flags appropriately
// Merge after commit
mergeChangesIntoParent();
}
/**
* INTERNAL:
* Traverse the object to find references to objects not registered in this unit of work.
*/
public void discoverUnregisteredNewObjects(Object clone, IdentityHashtable knownNewObjects, IdentityHashtable unregisteredExistingObjects, IdentityHashtable visitedObjects) {
// This define an inner class for process the itteration operation, don't be scared, its just an inner class.
DescriptorIterator iterator = new DescriptorIterator() {
public void iterate(Object object) {
// If the object is read-only the do not continue the traversal.
if (isClassReadOnly(object.getClass()) || isObjectDeleted(object)) {
this.setShouldBreak(true);
return;
}
//check for null mapping, this may be the first iteration
if ((getCurrentMapping() != null) && ((ForeignReferenceMapping)getCurrentMapping()).isCascadePersist() ){
((RepeatableWriteUnitOfWork)getSession()).registerNewObjectForPersist(object, new IdentityHashtable());
}else{
if (!getCloneMapping().containsKey(object)){
if (! checkForUnregisteredExistingObject(object)){
throw new IllegalStateException(ExceptionLocalization.buildMessage("new_object_found_during_commit", new Object[]{object}));
}else{
((IdentityHashtable)getUnregisteredExistingObjects()).put(object, object);
this.setShouldBreak(true);
return;
}
}
}
}
};
//set the collection in the UnitofWork to be this list
setUnregisteredExistingObjects(unregisteredExistingObjects);
iterator.setVisitedObjects(visitedObjects);
iterator.setResult(knownNewObjects);
iterator.setSession(this);
// When using wrapper policy in EJB the iteration should stop on beans,
// this is because EJB forces beans to be registered anyway and clone identity can be violated
// and the violated clones references to session objects should not be traversed.
iterator.setShouldIterateOverWrappedObjects(false);
iterator.startIterationOn(clone);
}
/**
* INTERNAL:
* Has writeChanges() been attempted on this UnitOfWork? It may have
* either suceeded or failed but either way the UnitOfWork is in a highly
* restricted state.
*/
public boolean isAfterWriteChangesButBeforeCommit() {
//dont' check for writechanges failure.
return (getLifecycle() == CommitTransactionPending);
}
/**
* INTERNAL:
* Return if the object has been deleted in this unit of work.
*/
public boolean isObjectDeleted(Object object) {
if(super.isObjectDeleted(object)) {
return true;
} else {
if(unregisteredDeletedObjectsCloneToBackupAndOriginal != null) {
if(unregisteredDeletedObjectsCloneToBackupAndOriginal.containsKey(object)) {
return true;
}
}
if (hasObjectsDeletedDuringCommit()) {
return getObjectsDeletedDuringCommit().containsKey(object);
} else {
return false;
}
}
}
/**
* INTERNAL:
* For synchronized units of work, dump SQL to database
*/
public void issueSQLbeforeCompletion() {
super.issueSQLbeforeCompletion(false);
if (this.cumulativeUOWChangeSet != null && this.getUnitOfWorkChangeSet() != null){
// unit of work has been committed so it's ok to set the cumulative into the UOW for merge
this.cumulativeUOWChangeSet.mergeUnitOfWorkChangeSet((UnitOfWorkChangeSet)this.getUnitOfWorkChangeSet(), this, true);
setUnitOfWorkChangeSet(this.cumulativeUOWChangeSet);
}
commitTransactionAfterWriteChanges(); // this method will commit the transaction
// and set the transaction flags appropriately
}
/**
* INTERNAL:
* Merge the attributes of the clone into the unit of work copy.
*/
public Object mergeCloneWithReferences(Object rmiClone, int cascadePolicy, boolean forceCascade) {
Object mergedObject = super.mergeCloneWithReferences(rmiClone, cascadePolicy, forceCascade);
if (mergedObject != null) {
// This will assign a sequence number to the merged object if it
// doesn't already have one (that is, it is a new object).
assignSequenceNumber(mergedObject);
}
return mergedObject;
}
/**
* INTERNAL:
* This method is used internally to update the tracked objects if required
*/
public void updateChangeTrackersIfRequired(Object objectToWrite, ObjectChangeSet changeSetToWrite, UnitOfWorkImpl uow, ClassDescriptor descriptor) {
descriptor.getObjectChangePolicy().updateWithChanges(objectToWrite, changeSetToWrite, uow, descriptor);
}
/**
* INTERNAL:
* This method will cause the all of the tracked objects at this level to have
* their changes written to the database. It will then decrement the depth
* level.
*/
public void writeChanges() {
if(unregisteredDeletedObjectsCloneToBackupAndOriginal == null) {
unregisteredDeletedObjectsCloneToBackupAndOriginal = new IdentityHashtable(2);
}
IdentityHashtable allObjectsList = new IdentityHashtable();
IdentityHashtable visitedNodes = new IdentityHashtable(2);
IdentityHashtable newObjects = new IdentityHashtable(2);
IdentityHashtable existingObjects = new IdentityHashtable(2);
IdentityHashtable insertedNewObjects = new IdentityHashtable(2);
for (Enumeration clones = getCloneMapping().keys(); clones.hasMoreElements();){
Object object = clones.nextElement();
discoverUnregisteredNewObjects(object, newObjects, existingObjects, visitedNodes);
allObjectsList.put(object, object);
}
for (Enumeration newClones = getNewObjectsCloneToOriginal().keys();newClones.hasMoreElements();){
Object object = newClones.nextElement();
assignSequenceNumber(object);
insertedNewObjects.put(object, object);
// add potentially newly discovered new objects
allObjectsList.put(object, object);
}
if (getUnitOfWorkChangeSet() == null) {
setUnitOfWorkChangeSet(new UnitOfWorkChangeSet());
}
calculateChanges(allObjectsList, (UnitOfWorkChangeSet)getUnitOfWorkChangeSet());
// write those changes to the database.
UnitOfWorkChangeSet changeSet = (UnitOfWorkChangeSet)getUnitOfWorkChangeSet();
if (!changeSet.hasChanges() && !changeSet.hasForcedChanges() && ! this.hasDeletedObjects() && ! this.hasModifyAllQueries()){
return;
}
try {
commitToDatabaseWithPreBuiltChangeSet(changeSet, false);
this.writesCompleted();
} catch (RuntimeException ex) {
setLifecycle(WriteChangesFailed);
throw ex;
}
//bug 4730595: fix puts deleted objects in the UnitOfWorkChangeSet as they are removed.
getDeletedObjects().clear();
// unregister all deleted objects,
// keep them along with their original and backup values in unregisteredDeletedObjectsCloneToBackupAndOriginal
Enumeration enumDeleted = getObjectsDeletedDuringCommit().keys();
while(enumDeleted.hasMoreElements()) {
Object deletedObject = enumDeleted.nextElement();
Object[] backupAndOriginal = {getCloneMapping().get(deletedObject), getCloneToOriginals().get(deletedObject)};
unregisteredDeletedObjectsCloneToBackupAndOriginal.put(deletedObject, backupAndOriginal);
unregisterObject(deletedObject);
}
getObjectsDeletedDuringCommit().clear();
if(this.cumulativeUOWChangeSet == null) {
this.cumulativeUOWChangeSet = (UnitOfWorkChangeSet)getUnitOfWorkChangeSet();
} else {
//merge those changes back into the backup clones and the final uowChangeSet
this.cumulativeUOWChangeSet.mergeUnitOfWorkChangeSet((UnitOfWorkChangeSet)getUnitOfWorkChangeSet(), this, true);
}
//clean up
setUnitOfWorkChangeSet(new UnitOfWorkChangeSet());
Enumeration enumtr = insertedNewObjects.elements();
while (enumtr.hasMoreElements()) {
Object clone = enumtr.nextElement();
Object original = getNewObjectsCloneToOriginal().remove(clone);
if (original != null) {
getNewObjectsOriginalToClone().remove(original);
//no longer new to this unit of work
getCloneToOriginals().put(clone, original);
}
}
}
/**
* INTERNAL:
* Called only by registerNewObjectForPersist method,
* and only if newObject is not already registered.
* If newObject is found in
* unregisteredDeletedObjectsCloneToBackupAndOriginal then it's re-registered,
* otherwise the superclass method called.
*/
protected void registerNotRegisteredNewObjectForPersist(Object newObject, ClassDescriptor descriptor) {
if(unregisteredDeletedObjectsCloneToBackupAndOriginal != null) {
Object[] backupAndOriginal = (Object[])unregisteredDeletedObjectsCloneToBackupAndOriginal.remove(newObject);
if(backupAndOriginal != null) {
// backup
getCloneMapping().put(newObject, backupAndOriginal[0]);
// original
registerNewObjectClone(newObject, backupAndOriginal[1], descriptor);
// Check if the new objects should be cached.
registerNewObjectInIdentityMap(newObject, newObject);
return;
}
}
super.registerNotRegisteredNewObjectForPersist(newObject, descriptor);
}
/**
* INTERNAL:
* This is internal to the uow, transactions should not be used explictly in a uow.
* The uow shares its parents transactions.
*/
public void rollbackTransaction() throws DatabaseException {
if (this.shouldTerminateTransaction || getParent().getTransactionMutex().isNested()){
super.rollbackTransaction();
}else{
//rollback called which means txn failed.
//but rollback was stopped by entitytransaction which means the
//transaction will want to call release later. Make sure release
//will rollback transaction.
setWasTransactionBegunPrematurely(true);
}
}
/**
* INTERNAL
* Synchronize the clones and update their backup copies.
* Called after commit and commit and resume.
*/
public void synchronizeAndResume() {
if(this.shouldClearForCloseInsteadOfResume()) {
this.clearForClose(false);
} else {
this.cumulativeUOWChangeSet = null;
this.unregisteredDeletedObjectsCloneToBackupAndOriginal = null;
super.synchronizeAndResume();
}
}
/**
* INTERNAL:
* Called only by UnitOfWorkIdentityMapAccessor.getAndCloneCacheKeyFromParent method.
* Return unregisteredDeletedClone corresponding to the passed original, or null
*/
public Object getUnregisteredDeletedCloneForOriginal(Object original) {
if(unregisteredDeletedObjectsCloneToBackupAndOriginal != null) {
Enumeration keys = unregisteredDeletedObjectsCloneToBackupAndOriginal.keys();
Enumeration values = unregisteredDeletedObjectsCloneToBackupAndOriginal.elements();
while(keys.hasMoreElements()) {
Object deletedObjectClone = keys.nextElement();
Object[] backupAndOriginal = (Object[])values.nextElement();
Object currentOriginal = backupAndOriginal[1];
if(original == currentOriginal) {
return deletedObjectClone;
}
}
}
return null;
}
/**
* INTERNAL:
* Wraps the oracle.toplink.essentials.exceptions.OptimisticLockException in a
* javax.persistence.OptimisticLockException. This conforms to the EJB3 specs
* @param commitTransaction
*/
protected void commitToDatabase(boolean commitTransaction) {
try {
super.commitToDatabase(commitTransaction);
} catch (oracle.toplink.essentials.exceptions.OptimisticLockException ole) {
throw new javax.persistence.OptimisticLockException(ole);
}
}
/**
* INTERNAL:
* This is internal to the uow, transactions should not be used explictly in a uow.
* The uow shares its parents transactions.
*/
public void commitTransaction() throws DatabaseException {
if (this.shouldTerminateTransaction || getParent().getTransactionMutex().isNested()){
super.commitTransaction();
}
}
public void setShouldTerminateTransaction(boolean shouldTerminateTransaction) {
this.shouldTerminateTransaction = shouldTerminateTransaction;
}
public void setShouldClearForCloseInsteadOfResume(boolean shouldClearForCloseInsteadOfResume) {
this.shouldClearForCloseInsteadOfResume = shouldClearForCloseInsteadOfResume;
}
public boolean shouldClearForCloseInsteadOfResume() {
return shouldClearForCloseInsteadOfResume;
}
}
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